A novel translocation, t(2;5)(p23;q35), in childhood phagocytic large T-cell lymphoma mimicking malignant histiocytosis.

We report a novel chromosome translocation--t(2;5)(p23;q35) or its variant, t(2;5;13)(p23;q35;q12)--in 3 patients with peripheral T-cell lymphoma. All 3 were female children who had peripheral lymphadenopathy without organomegaly and underwent complete remission with or without chemotherapy. Their tumors were characterized histologically by predominant large cells, at times showing phagocytosis, and immunologically by peripheral T-cell phenotype and expression of Ki-1 antigen and epithelial membrane antigen (EMA). Since the same translocation has been reported in the literature in 4 patients with malignant histiocytosis (MH), and our patients had histologic features suggestive of that disease, it is likely that many tumors previously interpreted as MH are actually phagocytic large T-cell lymphoma carrying this translocation.